CARROT SEED GERMINATION AND VIGOR IN RESPONSE TO TEMPERATURE AND UMBEL ORDERS

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1 Crrot seed germintion nd vigor 145 CRROT SEED GERMINTION ND VIGOR IN RESPONSE TO TEMPERTURE ND UMBEL ORDERS Rosene Sous Pereir; Wrley Mrcos Nscimento*; Jiro Vidl Vieir Emrp Hortliçs - C.P Brsíli, DF - Brsil. *Corresponding uthor <wmn@cnph.emrp.r> BSTRCT: Severl fctors my influence crrot (Ducus crot L.) crop estlishment. High tempertures (35-4 C), for instnce, my dely or inhiit crrot seed germintion in the field nd so compromise the stnd estlishment. Crrot seeds from superior umel orders usully hve etter physiologicl qulity thn those of lower umel orders. These seeds from superior umel orders my lso show etter performnce in dverse conditions. In ddition, seeds from different ges show differences in vigor, which ffect the stnd estlishment, minly under dverse conditions. The im of this study ws to verify the germintion t high tempertures nd the crrot seed vigor of different umel orders of 'Brsíli', s well s the different 'lvord' seed lots. Preliminrily, 'Brsili' seeds were incuted t tempertures rnging from 2 to 36 C. lso, seeds from the primry, secondry nd tertiry umel orders hrvested seprtely from sic seed production field nd seeds from lots hrvested in 1998, 1999 nd 2 were nlyzed to the following tests: germintion t 2 C (optimum) nd 35 C (dverse), ccelerted ging, cold test, seedling emergence in greenhouse nd mss of seeds. High tempertures reduced crrot seed germintion. Seeds germinted etter t 2 C thn 35 or 36ºC. Seeds from primry nd secondry orders, s well s less ged seed lots, hd higher vigor nd germintion t high temperture. Key words: Ducus crot L., thermo-inhiition, physiologicl qulity GERMINÇÃO E VIGOR DE SEMENTES DE CENOUR EM RESPOST TEMPERTUR E ORDENS DE UMBEL RESUMO: Vários ftores podem influencir no estelecimento d cultur d cenour (Ducus crot L.). lts temperturs (35-4 C), por exemplo, podem retrdr ou iniir germinção ds sementes de cenour no cmpo, comprometendo ssim o estelecimento de plântuls. Sementes oriunds de umels de ordem superior gerlmente presentm melhor qulidde fisiológic do que quels de menor ordem. Ests sementes podem presentr um melhor performnce no cmpo, principlmente so condições dverss. Lotes de sementes rmzendos por diferentes períodos podem tmém presentr diferençs de vigor o que poderá fetr o estelecimento de plântuls no cmpo, principlmente em condições dverss. O presente trlho teve como ojetivo estudr germinção em condições de lts temperturs e o vigor ds sementes de diferentes ordens de umels de cenour cv. Brsíli, em como de diferentes lotes d cv. lvord. Sementes de cenour 'Brsíli' form incuds em temperturs vrindo de 2 36 C. ind, sementes d primeir, segund e terceir ordens colhids seprdmente em um cmpo de produção de sementes ásics e sementes provenientes de lotes produzidos nos nos de 1998, 1999 e 2 form nlisds qunto germinção temperturs de 2 C (ótim) e 35 C (dvers), envelhecimento celerdo, teste de frio, emergênci de plântuls em cs de vegetção e mss de sementes. Temperturs elevds reduzirm germinção ds sementes de cenour. s sementes germinrm melhor tempertur de 2 C do que 35 ou 36ºC. Sementes oriunds de ordens primári e secundári, em como lotes mis novos, presentrm mior vigor e germinção em tempertur elevd. Plvrs-chve: Ducus crot L., termo-iniição, qulidde fisiológic INTRODUCTION The crrot (Ducus crot L.) plnt in its looming stge produces centrl florl stem tht contins t the tip centrl inflorescence, known s primry umel, which rmifies nd origintes the secondry, tertiry nd quternry umels. The umel size Sci. gric. (Pircic, Brz.), v.65, n.2, p , Mrch/pril 28 decreses s the numer of the order increses. The size, vigor nd germintion of crrot seeds, which determine the seed qulity, vry ccording to the umel order (Hwthorn & Toole, 1962; Cstro & ndrews, 1971; Gry & Steckel, 1983; Krrup & Villnuev, 1977; Viggino, 1984; Nscimento, 1991; Rodo et. l., 21).

2 146 Pereir et l. The contriution of ech umel order to the crrot seed production depends on oth cultivr nd edphoclimtic conditions. Nscimento (1991), oserved tht primry umel of 'Brsíli' crrot contriuted to 11%, secondry to 58% nd tertiry to 31% of the totl seed production. Seed qulity decresed s the umel order incresed (Nscimento, 1991). Superior umel orders lso produced seeds of higher size or mss (Cstro & ndrews, 1971; Cstellne, 1982; Krrup & Durn, 1982; Crdoso, 2). In open pollinted cultivrs, s 'Brsíli', there is still high genetic diversity, which is one of the resons why seed qulity stndrds do not seem to e very well defined, with high vrition in seed qulity in terms of germintion nd vigor (Bittencourt, 1991). These trits my compromise the crop estlishment under some conditions. High tempertures (35-4 C) for exmple, cn dely or inhiit crrot seed germintion nd compromise the stnd estlishment in the field (Crneiro & Guedes, 1992; Cntliffe & Elll, 1994; Pereir & Nscimento, 22; Pereir et l., 27; Nscimento & Pereir, 27). The im of this study ws, therefore, to verify the germintion t high temperture nd vigor of crrot seeds from different umel orders of Brsíli nd from different lots of lvord. MTERIL ND METHODS Study 1: Evlution of Brsíli crrot seed germintion t different tempertures In this preliminry study, four replictions of 5 seeds of Brsíli crrot were plced in plstic ox contining two germintion ppers wetted with 15 ml of fungicide solution (iprodione + thirm 3:1-4 g L -1 distilled wter). Seeds were incuted in n NKSystem type chmer to germinte under rtificil light, t the constnt tempertures of 2, 24, 28, 32 nd 36ºC. Evlutions were performed fter 14 dys of incution nd the results expressed in verge percentge of germinted seeds (primry root protrusion). Dt were sumitted to vrince nlysis, nd the verges were compred y Tukey test (P <.5). Percentge dt hd previously een trnsformed ccording to rc sign. Study 2: Vigor nd germintion of Brsíli crrot seeds from different umel orders This study ws crried out in Brsíli, DF, Brzil, etween Jnury 23 nd Ferury 25. Roots of Brsíli crrot produced during the summer nd then vernlized in cold storge room t 4ºC nd 9-95% RH for 35 dys, were used to otin seeds. fter this period, the roots were trnsplnted into the greenhouse, 24 hours fter eing tken out of the storge room. Distnces of.8 m etween rows nd.3 m etween plnts were used. During the flowering, ees (Trigon spinipes) nd flies (Musc domestic) were used for pollintion. Primry, secondry nd tertiry umels were hrvested seprtely, dried in n oven t 35 C for 24 hours, nd then, threshed nd processed mnully. Seeds were nlyzed y the following tests: Germintion test: Four replictions of 5 seeds were plced in plstic ox contining two germintion ppers wetted with 15 ml of fungicide solution (iprodione + thirm 3:1-4 g L -1 distilled wter). Seeds were incuted in BOD type chmer t 2 (optimum) nd 35ºC (dverse). Evlution occurred fter seven nd 14 dys of incution, nd the results were expressed s n verge percentge of germinted seeds (primry root protrusion). First-count test: Crried out with the germintion test, y clculting the verge percentge of germinted seeds (primry root protrusion) fter seven dys of incution. Seed mss (g): Four replictions of seeds were weighted on n nlyticl scle, to three deciml point. ccelerted ging: Firstly, the seed moisture content ws determined ccording to the Rules for Seed nlysis (Brsil, 1992). Seed smples of 3. g for ech umel order were plced over screen into the gerox with 4 ml of distilled wter, for 72 hours t 42ºC. Then, four replictions of 5 seeds were incuted t 2ºC, following the sme methodology of the germintion test, nd the evlution fter seven dys of incution. Cold test: Four replictions of 5 seeds were plced in plstic ox contining two germintion ppers wetted with 15 ml of fungicide solution (iprodione + thirm 3:1-4 g L -1 distilled wter) nd incuted for seven dys in BOD type chmer, t ºC, then trnsferred to 25ºC, where they were evluted fter 24 hours (primry root protrusion). Emergence of seedlings in greenhouse: Four replictions of 5 seeds were sowed on Ferury 14, 25 in multi-cellulr expnded polystyrene trys contining the commercil sustrte nd plced in greenhouse, where the temperture etween h nd 14h rnged from 35 to 4ºC. Evlutions occurred fter seven nd 14 dys of sowing, nd the results were expressed s n verge percentge of emerged seedlings. Sci. gric. (Pircic, Brz.), v.65, n.2, p , Mrch/pril 28

3 Crrot seed germintion nd vigor 147 The dt otined ws sumitted for vrince nlysis, nd the verges of tretments were compred y Duncn test (P <.5). The dt in percentges hd previously een trnsformed through the rc sin. Study 3: Vigor nd germintion of lvord crrot seeds from different seed lots Bsic seed lots of lvord crrot produced y Emrp Vegetles, Brsíli, DF in 1998, 1999 nd 2, nd stored in cold chmer t 5ºC nd 4-45% RH, were evluted through the germintion test, first count test, cold test, emergence of seedlings in greenhouse nd seed mss, s descried in the Study 1. The experimentl design ws entirely rndomized, with four replictions, nd the verges were compred y the Duncn test (P <.5). Dt in percentge hd previously een trnsformed ccording to rc sin. RESULTS ND DISCUSSION Study 1: Evlution of Brsíli crrot seed germintion t different tempertures Seeds incuted t tempertures rnging from 2 to 32ºC hd the sme germintion pttern (Figure 1). t 2ºC, seed germintion ws 85%; wheres t 36ºC, only 27% of seeds germinted. Temperture is considered n importnt fctor ffecting the rte nd percentge of germintion nd emergence (Nscimento, 2). High tempertures hve strong influence on crrot seed germintion. For exmple, in some genotypes no germintion is oserved; nd in others, germintion is drsticlly reduced (Pereir et l., 27). In similr study, Brsíli crrot seeds germinted 91% t 25ºC, while t 35ºC, germintion decresed to 47% (Crneiro & Guedes, 1992). Study 2: Vigor nd germintion of Brsíli crrot seeds from different umel orders fter hrvesting, seed moisture content from primry, secondry nd tertiry umels ws 7.7; 6. nd 7.6%, respectively. Differences were oserved in Germintion (%) Temperture (ºC) Figure 1 - Brsíli crrot seed germintion t different tempertures, under light. (CV = 6.6%). Brsíli, DF, Brzil, 25. Mens followed y the sme letter were not different (Tukey test, P <.5). seed germintion t different tempertures, with superiority t 2 C. Germintion t 2 C ws higher for ll umel orders, which vried etween 91 nd 95% (Figure 2). Crrot seeds germinte well etween 8 C nd 3ºC, in which the idel rnge for otining the mximum potentil is etween 2 nd 3ºC (Lim Júnior, 1999). t 35ºC, there ws reduction in seed germintion (Figure 3). Crrot seeds of Kuronn nd Brsíli showed low germintion t 35 C (Crneiro & Guedes, 1992; Pereir & Nscimento, 22). In the present study, no differences were oserved mong Germintion (%) Germintion (%) Umel orders Figure 2 - Germintion fter 7 ( ) nd 14 ( ) dys t 2ºC of Brsíli crrot seeds from different umel orders (CV = 4.7% nd 3.6% respectively). Brsíli, DF, Brzil, 25. Mens followed y the sme upper cse letter nd the sme lower cse letter were not different (Duncn test, P <.5) Primry Primári Secundári Secondry Terciári Tertiry Primári Primry Secundári Secondry Tertiry Terciári Umel orders Figure 3 - Germintion fter 7 ( ) nd 14 ( ) dys t 35ºC of Brsíli crrot seeds from different umel orders (CV = 13.3% nd 11.9% respectively). Brsíli, DF, Brzil, 25. Mens followed y the sme upper cse letter nd the sme lower cse letter were not different (Duncn test, P <.5). Sci. gric. (Pircic, Brz.), v.65, n.2, p , Mrch/pril 28

4 148 Pereir et l. the umels orders for the first count germintion. However, there ws difference in seed germintion percentge t 35 C. Seeds from primry nd secondry umels, lthough did not show ny difference, hd higher germintion thn the seeds from tertiry umels (Figure 3). Using progenies from Brsili crrot popultion, Pereir et l. (27) found etter performnce t 35 C in seeds from primry umels when compred to those from secondry ones. Seeds from superior umel orders hve higher size nd density, presenting etter seed development. Seeds with fully mture emryos nd high mounts of reserves re potentilly the most vigorous ones (Crvlho & Nkgw, 1983). In ddition, vigor of seeds is closely relted to performnce under dverse conditions (Heydecker, 1972). Differences mong the umel orders were oserved in the emergence on the seventh dy t greenhouse. On the 14 th dy, seeds from primry umels performed etter thn the other umel orders (Figure 4). s previously mentioned, high tempertures were oserved during the test, which might hve influenced the results. Seeds from primry umel showed high vigor y ccelerte ging test in reltion to the other umel orders (Figure 5). lso, the cold test reveled difference mong the tretments; seeds from primry, secondry nd tertiry umel orders germinted in this test, 73, 58 nd 5%, respectively (Figure 5). The thermo stress conditions to which seeds of different umel orders were sumitted cused decresing of seed vigor. The sttisticl nlysis reveled differences in seed mss mong umels, with decrese of mss s the umel order incresed (Figure 6). These results Seedling emergence (%) B Primry Primári Secondry Secundári Tertiry Terciári Umel orders Figure 4 - Seedling emergence in greenhouse fter 7 ( ) nd 14 ( ) dys of Brsíli crrot seeds from different umel orders. (CV = 7.8% nd 6.1% respectively). Brsíli, DF, Brzil, 25. Mens followed y the sme upper cse letter nd the sme lower cse letter were not different (Duncn test, P <.5). B hve een similrly oserved y Cstro & ndrews (1971), Szfirowsk (1994) nd Crdoso (2). Nscimento (1991), however, did not oserve ny difference in this trit mong the different umel orders using the sme genotype. Using 'Brsíli' crrot, Crdoso (2) otined mss of 1, seeds of 2.18 g, 1.63 g nd 1.45 g for seeds from primry, secondry nd tertiry umel orders, respectively. These differences my occur, s the mss of crrot seeds lso vries ccording to the seed lot nd the production timing (Gry et l., 1988). s superior umels usully produce seeds with higher germintion nd vigor, the primry nd secondry umels could e hrvested seprtely nd used in regions nd/or t sowing times where conditions of more stress, including high tempertures, occur. Study 3: Vigor nd germintion of lvord crrot seeds from different seed lots Seed lots from 1998, 1999 nd 2 hd moisture content of 9.; 9.5 nd 11.% respectively, fter Germintion (%) Umel orders Figure 5 - ccelerte ging test ( ) nd cold test (%) ( ) of seeds from different umel orders of 'Brsíli' crrot. (CV = 6.% nd 6.8% respectively). Brsíli, DF, Brzil, 25. Mens followed y the sme upper cse letter nd the sme lower cse letter were not different (Duncn test, P <.5). Seed mss (g) Primári Primry Secundári Secondry Tertiry Terciári B Primári Primry Secondry Secundári Tertiry Terciári Umel orders Figure 6 - Mss of seeds from different umel orders of Brsíli crrot. (CV = 2.1%). Brsíli, DF, Brzil, 25. Mens followed y the sme letter were not different (Duncn test, P <.5). B c c Sci. gric. (Pircic, Brz.), v.65, n.2, p , Mrch/pril 28

5 Crrot seed germintion nd vigor 149 Tle 1 - First counting of germintion t 2ºC (FC 2) nd 35ºC (FC 35), totl germintion t 2ºC (TG 2) nd 35ºC (TG 35), seedling emergence (SE), cold test (CT) nd seed mss (M) from different lots of lvord crrot. Emrp Vegetles, Brsíli, DF, 25. Lots FC 2 TG 2 FC 35 TG 35 SE CT M % g c c CV (%) Mens followed y the sme letter were not different (Duncn test, P <.5). eing tken out from the cold storge room, nd immeditely efore crrying out the tests. t 2ºC, seed lots did not differ, lthough the seed lot from 2 showed numericlly higher germintion (Tle 1). t 35 C, in the first germintion counting, the seed lots showed differences. The 2 lot hd the est performnce t high tempertures, despite the high reduction in germintion oserved in this study (Tle 1). In nother study, different crrot seed lots of Orlndo Gold cultivr hd lso considerle reduction in germintion t 35ºC (Cntliffe & Elll, 1994). When the lots re stored for long periods, seed vigor tends to decrese, which cn ffect negtively their potentil for field estlishment, minly under high tempertures (Tle 1). The 2 seed lot showed the higher emergence, followed y the 1999 nd 1998 seed lots. The high vigor of seeds is fundmentl fctor for crop estlishment, required to tolerte environmentl stress (Heydecker, 1972), including high tempertures. The cold test t ºC ws very efficient for the seprtion of different vigor levels (Tle 1), compred to the seedling emergence in the sustrte. This test ws more comprehensive thn the germintion test t 2ºC for the seprtion of crrot seed lots (Hegrty, 1971; Peluzio, 1999). The mss of seeds otined in the seed lots from 2, 1999 nd 1998 showed significnt differences:.212 g,.188 g nd.185 g, respectively (Tle 1). Severl fctors, such s edphoclimtic conditions nd seed mturtion, my hve contriuted to these differences nd ffected seed vigor. In nother study, crrot seed lots from 1992 displyed etter performnce in vigor tests, compred to those produced in 1989 nd 199, where germintion ws reduced to zero (ndrde et l., 1995). These uthors oserved tht the ppliction of the vigor test fcilitted the comprison of the seed lots. This might e of high relevnce for decision mking s regrds to the seed storge, commerciliztion nd use. For exmple, in the present study, lots from 1998 nd 1999, even when showing elevted germintion levels in the lortory germintion test, displyed lower vigor in different tests, which will certinly ffect the estlishment of seedlings under conditions of stress in the field. In order to otin etter performnce in the field, minly under dverse conditions of high tempertures, it would e dvisle to use seeds from primry nd secondry umels, s well s higher vigor seeds. CONCLUSIONS The increse of the temperture to C drsticlly reduced crrot seed germintion. Seeds from primry nd secondry umel orders showed etter performnce t high tempertures thn those from terciry umels. Seed lots with higher vigor displyed etter performnce t high tempertures. CKNOWLEDGEMENTS To CNPq for finncil support, grnt no /24-8. REFERENCES NDRDE, R.N.B.; SNTOS, D.S.B.; SNTOS FILHO, B.G.; VER, D.C. Correlção entre testes de vigor em sementes de cenour rmzends por diferentes períodos. Pesquis gropecuári Gúch, v.1, p , BITTENCOURT, M.L.C. Qulidde ds sementes e vlição ds progênies de meios-irmãos de cenour (Ducus crot L.) Brsíli. Viços: Universidde Federl de Viços, p. Dissertção (Mestrdo). BRSIL. Ministério d gricultur e d Reform grári. Regrs pr nálise de sementes. Brsíli: SND/DNDV/CLV, p. CNTLIFFE, D.J.; ELBLL, M. Improved germintion of crrot t stressful high temperture y seed priming. Procedings of the Florid Stte Horticulturl Society, v.7, p , CRDOSO,.I.I. Produção e qulidde de sementes de cenour ds cultivres Brsíli e Crndí. Brgnti, v.59, p.77-81, 2. CRNEIRO, J.W.P.; GUEDES, T.. Influênci d tempertur no desempenho germintivo de sementes de cenour (Ducus crot L.), vlid pel função de distriuição de Weiull. Revist Brsileir de Sementes, v.14, p , CRVLHO, N.M.; NKGW, J. Sementes: ciênci, tecnologi e produção. 2 ed. Cmpins: Fundção Crgill, p. Sci. gric. (Pircic, Brz.), v.65, n.2, p , Mrch/pril 28

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